If this tool helped you, you can buy us a coffee ☕
Accurately calculate your cup and bra size using your bust and underbust measurements to find the perfect fitting bra.
Measure the circumference at the fullest part of your bust. Measuring with your body tilted forward 45 degrees is more accurate.
Measure the circumference of your ribcage at the base of your breasts, horizontally.
Enter measurements to start calculating
Random Chinese Name Generator
Bulk generate random Chinese names by gender, length, and surname for novels, games, and character design.
Chinese to Pinyin Converter
Convert Chinese characters (Hanzi) to Pinyin with tone marks or numbers. Features smart polyphone recognition and a dedicated name mode.
Noise Detector
Measure environmental noise decibel levels in real-time using your device's microphone. Evaluate noise levels at home, in the office, or in public spaces to protect your hearing.
Simplified & Traditional Chinese Converter
Accurately convert between Simplified Chinese, Standard Traditional, Taiwanese Traditional, and Hong Kong Traditional Chinese. Supports custom dictionaries.
Random Chinese Name Generator
Bulk generate random Chinese names by gender, length, and surname for novels, games, and character design.
Chinese to Pinyin Converter
Convert Chinese characters (Hanzi) to Pinyin with tone marks or numbers. Features smart polyphone recognition and a dedicated name mode.
Noise Detector
Measure environmental noise decibel levels in real-time using your device's microphone. Evaluate noise levels at home, in the office, or in public spaces to protect your hearing.
Simplified & Traditional Chinese Converter
Accurately convert between Simplified Chinese, Standard Traditional, Taiwanese Traditional, and Hong Kong Traditional Chinese. Supports custom dictionaries.
Fuel Consumption Calculator
Calculate key data like fuel consumption per 100km (L/100km) and cost per kilometer based on your driving distance, fuel volume, and gas price.
When shopping for a bra, relying solely on feeling or experience often makes it difficult to find a truly well-fitting size, leading to discomfort, slipping straps, or breast distortion. This tool helps you quickly determine your accurate bra size through scientific measurement and calculation. It is based on standard bra size conversion logic: enter your measured bust (the circumference at the fullest part of your breasts) and underbust (the circumference just under your breasts), and the system will automatically calculate the difference. It then compares this to international size charts to output the corresponding cup letter (e.g., A, B, C, D) and band size (e.g., 34, 36), ultimately generating a complete bra size recommendation (e.g., 34B, 36C). The core formula for cup size is: Cup Size = Bust Measurement - Underbust Measurement. This difference directly determines the depth of the cup.
1. What should I pay attention to when measuring? How can I ensure accuracy?
When measuring, keep the tape measure level and snug against the skin, but not too tight. For the bust measurement, you can lean forward slightly to let your breasts hang naturally. For the underbust, breathe normally and measure at the end of an exhale. To ensure accuracy, we recommend measuring 2-3 times and taking the average.
2. If the result is 34B, do I have to buy a 34B bra?
Not necessarily. The calculated result is a scientific baseline. When actually purchasing, you also need to consider brand differences, breast shape (e.g., shallow/conical, round/hemispherical), tissue distribution, and personal comfort preferences. If you have softer breast tissue or a wider distribution, you might need to size up in the cup (e.g., choose a C cup).
1. Input Limits: Please enter positive integers in centimeters. Measurement errors may lead to inaccurate results, so ensure your measuring technique is correct.
2. Understanding Results: The calculated result is a general reference. Different bra brands and styles may have sizing variations, so we recommend trying them on for the best fit.
3. Privacy and Security: All calculations are performed locally in your browser. We do not collect or upload any of your body measurement data.
4. Special Breast Shapes: For breasts that are particularly shallow, pendulous (sagging), or wide-set, the calculated results may not be perfectly applicable. We recommend consulting a professional bra fitter.
Calculating bra size essentially maps three-dimensional human chest data into a standardized two-dimensional sizing system. Beyond the basic circumference difference, dimensions like breast projection and root width also affect the wearing experience. A typical calculation example is as follows: if the measured bust is 90 cm and the underbust is 75 cm, the difference is 15 cm. According to common size charts (a difference of 10-12.5 cm is roughly an A cup, 12.5-15 cm is a B cup, and 15-17.5 cm is a C cup), a 15 cm difference typically corresponds to a C cup. Combined with a 75 cm underbust, the recommended size is 75C (US 34C). However, please note that if the breast tissue is soft and widely distributed, a B cup might actually fit better; if the breasts are projected and firm, a C cup is more suitable. We recommend using this tool's result as a strong initial filter, making your final judgment based on the specific cut and style of the bra.
